X-ray apparatus



Feb. 5, 1935. BOuwERs 1,990,368

Y x-RAY' APPARATUS I Filed July 15, 1928 3 Sheets-Sheet 1 Feb. 5, 1935. A. BOUWERS X-RAY APPARATUS Filed July 13, L928 3 Sheets-Sheet 2 Invevjzfor: dizouwera, ,d fiw w Feb. 5, 1935. A. BOUWERS- 7 9 X-RAY APPARATUS Filed July 13, 1928 3 Sheets-Sheet 3 Patented Feb. 5, 1935 TAT-ES X-RAY APPARATUS Albert Bouwers, Eindhoven,

Netherlands, assignor Application July 13, 1928, Serial No. 292,390 In the Netherlands August 5, 1927 16 Claims. (01. 250-34) This invention forms a continuation in'part of my copending application Ser. No. 178,457, filed March 25, 1927, now Patent No. 1,948,005 and relates to an X-ray installation, and more particularly to one comprising an X-ray tube, a transformer, and at least one high tension cable, and to parts thereof.

Certain specific features described in this application and relating to the transformer are claimed in my copending divisional application Ser. No. 502,523 filed December 15, 1930, now Patent No. 1,891,139.

One object of the invention is to provide an X-ray installation in which all of the externally exposed parts of the transformer, of the X-ray tube and of the cables can be brought to ground potential by surrounding samewith metal envelopes which can be grounded during operation and thus these members can be displaced during operation without any danger of electric shocks.

The container of the X-ray tube may be cylindrical and made entirely of glass, the container being surrounded by a metal envelope, and, if required, an insulating substance may be placed between the container and the metal envelope. The high tension cables pass through the grounded metal envelope and are insulated therefrom.

Preferably, in connection with the invention, I use an X-ray tube the wall of the container of which is partly of metal, whereas the nonmetallic parts of the container wall are sur-' rounded by a metallic envelope.

Especially good results are obtained with X-ray tubes in which the metal wall portion of the container is insulated from both the cathode and the anti-cathode and in which the metal envelope is preferably secured to the metal portion of the container wall. In this case, it is advantageous to electrically connect the midpoint of the secondary winding of the transformer to the metal envelope of the transformer,

which also connects the transformer midpoint to ground.

As a high voltage difference exists between the grounded metal envelopes of the X-ray tube or of the transformer and the conductor of the cable leading through same, the cable is to be provided with adequate insulation. For this purpose, according to the invention, one or both cable ends are provided with a terminal piece of insulating material, through which passes the conductor of the cable. The cable terminal piece may have a diameter exceeding that of the cable and instead of having a smooth surface,

- terminal piece.

' rounds, at least partly,

it may have a corrugated surface to lengthen the leakage path.

Furthermore the terminal piece may have a snug fit with the insulation and conductor of the cable without intervening air-spaces. Preferablythe cable insulation extends within the One or more bar; or rod-shaped or cylindrical contact members may be used for the electrical connection of the conductors of the cable to one of the electrodes of the X-ray tube or to one end of the transformer winding, such members being connected to; the conductor of the cable and secured to its terminal piece. These connecting bar or rod-shaped or cylindrical members should have as large a radius of curvature as possible.

The surface of the terminal piece through which the cable conductor passes, should preferably form anoblique angle with the cable conductor 'soas to avoid parallel lines of force at that point which may cause a breakdown along the terminal surface. To improve the insulation at the anti-cathode end of the tube a block of insulating material may be disposed between the tube container and the surrounding metal envelope, which block surthe cooling rod of the anti-cathode and extends into the cavity formed by the reentrant portion of the glass wall of the container and at the same time tightly bears against the terminal piece provided on'the cable leading to the anti-cathode.

To insure a satisfactory electrical connection between this cable and the anti-cathode, the contact member of the terminal piece of the cable snugly fits into an aperture of the anti cathode cooling rod or embraces a projecting member provided on the cooling rod.

If no insulating block is used, the terminal piece itself should preferably form with the cooling rod a tight fit over at least part of their surfaces. Preferably the end of the cooling rod is made spherical and the cable terminal piece is provided with a corresponding spherical recess to fittingly surround same.

For the secure connection of the cable to the transformer, the terminal piece of the cable at the transformer-end tightly bears against a block of insulating material disposed within the transformer'housing or envelope. Secured to this block are one or more contact members which are electrically connected to the secondary winding of the transformer and which, for the electrical connection of the cable, engage the contacting member of the terminal piece of the corresponding cable, by either surrounding this member or being surrounded by same.

The incandescent cathode of the X-ray tube has two lead wires, and the terminal piece of the respective cable carries two contact members, which are preferably arranged concentrically with regard to each other. correspondingly, the two ends of the cathode are connected to two concentric contact members, whereby, for the connection of the cathode cable to the tube, the above two sets of concentric members are brought into engagement with each other.

To decrease the danger of breakdown there is provided at the cathode end of the tube a block of insulating material disposed between the container and the surrounding metal envelope. This block extends into the adjacent reentrant glass portion of the tube container and carries the contact members for the connection of the cable; the lead wires of the cathode also passing through the block. Preferably the insulating block is given such a shape that the terminal piece of the oathode cable tightly bears against same.

When the cables are connected to the X-ray tube and to the transformer respectively, the contact members of the cable terminal pieces engage the respective contact members of the X-ray tube and of the transformer over a large surface.

The respective terminal pieces of the cableare at least partly enclosed by the metal envelopes of the X-ray tube and of'the transformer.

The terminal piece preferably carries a metal ring at its end opposite to its contacting end, which ring surrounds the cable and tightlybears against the terminal piece. Thereby the contact surface between the metal ring .and the terrminal piece, instead a of being perpendicular to the cable conductor is preferably curved.

To secure the cable to the X-ray tube and to the transformer respectively, hoods may be used, which are apertured for the passage of the cable. The hoods at least partly surround their respective terminal pieces or the metal rings of the terminal piece and are secured to their respective metal envelope. A gland nut may serve as such a hood and may be screwed to the metal envelopes of the X-ray tube and of the transformer respectively. The hoods may also establish electrical connection between the outer sheath of the cable and the envelopes of the X-ray tube andv of the transformer respectively.

The installations according to the invention have the advantage that they can be set up and taken apart very easily and in a very short time, and the various parts can be made so light and so compact that the entire installation can be carried by a single person.

In order to facilitate the carrying of the transformer, a handle may be provided for the transformer which fits into the apertures of the transformer housing, provided there for the cables, and can be secured therein by means of gland nuts. Thus the handle closes the cable-receiving apertures when the cables are disconnected, and seals these apertures, whereby it also prevents the oil from spilling out through the apertures.

The invention will be more clearly understood by reference to the accompanying drawings illustrating an embodiment of the invention and in which:

' Figure 1 is a perspective View of an X-ray installation according to the invention, in which an Xray tube and a transformer are interconnected by high-tension cables, and the entire installation is provided with an outer conductive surface which is grounded.

Fig. 2 is a side view partly in section, and with parts broken away, showing the X-ray tube and the transformer with the interconnecting cables.

Fig. 3 is anenlarged cross-sectional side view showing parts of the cathode end of the X-ray tube of Fig. 2, with the cathode cable brought into registering position for its attachment to the tube.

Fig. 4 is an end View of the insulating block for the cathode end of the X-ray tube.

Fig. 5 is a partial sectional side view of the anticathode end of an X-ray tube, according to the invention, showing a modification in which an insulating block directly and snugly surrounds the cooling rod of the anti-cathode.

Fig. 6 is a side view of the transformer, with the handle secured thereto.

Referring to Fig. 2, there are shown connected to an X-ray tube 1, two high-tension cables 2 and 3 having outer metal sheaths 2 and 3' which connect the X-ray tube to a transformer 4.

The container of the X-ray tube consists of two cylindrical glass parts 5--5, provided with re-entrant end portions, and of a central metal part 6. The metal part 6 forms a sleeve which is sealed at'both its ends to the glass parts 55 of the container; the metal sleeve being preferably made of ferrochrome.

An anti-cathode 7 and an incandescent cathode 13, the latter surrounded by a focusing device 8, fall within the metal sleeve 6, from which they are insulated, each by the full extent of one of the glass parts 5- 5. The anti-cathode '7 and the focussing device 8 are sealed to the reentrant end of'their respective glass portion 5.

A ray-emitting Window 9 is provided in the metal sleeve 6 for the passage of the X rays. Secured to the anti-cathode '7 is a cooling rod 10 to conduct away the heat produced at a target 60 of the anti-cathode.

For the electrical connection of the cathode 13, there are provided lead wires 11 and 12, hermetically sealed in the press 14, the latter being carried by a. stem 15. The outer end of the stem 15 is sealed to the re-entrant glass por-= tion 5.

The focussing device 8 is of metal and is provided with an aperture 61. The cathode 13 is arranged in the rear of aperture 61 in such a manner that the electrons emitted by the cathode pass through the aperture toward the anticathode.

Secured to the metal sleeve 6 on both ends thereof are provided two similar outwardly flaring portions of a metal envelope 16, each surrounding the corresponding end of the X-ray tube and, together with the metal sleeve 6, constituting a substantially uninterrupted metal surface around the tube.

The metal envelope is provided with two apertures for the passage of the high tension cables 2 and 3, and is also provided at its two ends with a number of smaller apertures 17 (see Fig. 3) for the passage of air, which air can circulate between the X-ray tube and the metal envelope.

Interposed between the container of the tube and the metal envelope l6, and closely surrounding the container at its glass portions 55, are cylindrical bushings 1818 made of insulating material.

The anti-cathode cable 2 is a high tension cable having a single conductor 64 and the cath-' ode cable 3 is a high tension cable having two conductors 65 and 66. As stated, the cables 2 and 3 are metal-clad by sheaths 2 and 3' respectively, and are adapted to be electrically connected with their other ends to the transformer 4.

The transformer 4 comprises a primary winding 62 and a secondary winding 63, these windings being immersed in oil. The transformer comprises a substantially closed metal envelope or housing to which is connected the midpoint of the secondary winding 63, the housing 20 being grounded at 50.

Because of such connections, the voltage to which the insulation of the X-ray tube and of the cables is subjected in operation is but onehalf of the operating voltage. This brings about not only a saving of material, but also a compactness of the installation.

Above the windings 62 and 63 of the transformer, there is provided within the housing 20, a cross-plate 19 of insulating material.

The high tension cable 2 carries at its two ends, terminal pieces 23 and 24, and similarly the high tension cable 3 carries at its two ends terminal pieces 21 and 22. These terminal pieces are made of insulating material, for example of artificial resin, such as the material known under the trade name Bakelite.

The terminal pieces 21, 22, 23 and 24 have a substantially cylindrical shape and an outside diameter exceeding that of the cables. As more clearly appears from Fig. 3 the terminal pieces have a corrugated surface at their portions surrounding the cable end so as to lengthen the leakage path and to decrease the danger of electrical breakdown along this surface.

The cable extends with its insulation into the terminal pieces and tightly fits therein over its entire contacting surface without any intermediate airspace (see Fig. 3). The conductor of the cable extends beyond the insulation of the cable into the terminal piece and is preferably tightly embraced thereby.

At the point at which the conductor of anticathode cable 2 extends beyond the terminal pieces 23 and 24, it is secured to rod-shaped contact members 70 and 35 carried by the terminal pieces and serving to electrically connect the conductor of cable 2 to the anti-cathode 7 and to the anti-cathode side of the secondary winding of the transformer respectively.

The terminal piece 21 of the cathode cable 3 is provided with two concentric contact members 26 and 27 and its terminal piece 22 carries similar contact members 31 and 32. The contact members 2627 and 31- 32 are made with a sumciently large diameter to minimize corona effect and are electrically connected to the two cathode cable conductors 65 and 66 respectively (see Fig. 3).

The contact members 26 and 27 serve for the electrical connection of the cable conductors 65 and 66 with the lead-in wires 11 and 12 of the incandescent cathode 13.

The end surface of the terminal pieces is not perpendicular to the conductors and not parallel to the lines of force, but as indicated at 28 in Fig. 3, is sloped towards the cable conductor and the contact members 26 and 27.

The cooling rod 10, as shown in Fig. 2, is spherically rounded at its end 29 and is provided with a bore 30 which engages the contact member 70 of the cable 2. The end surface 67 of the terminal piece 23 is concaved to tightly fit and engage the corresponding portion of the cooling rod end 29.

The contact members provided at the transformer end of the cables 2 and 3 are similar to the contact members provided at the other ends of these cables. Thus, the cable 2 carries at each of its ends a rod-shaped contact member, whereas cable 3 carries at each of its ends two concentric cylindrical contact members.

Provided on the insulating block 19 of the transformer are contact members to engage the corresponding contact members of the terminal pieces 22 and 24 of the cables. More particularly, the contact member of the cable 2 engages a corresponding contact sleeve 36, whereas the concentric contact members 31 and 32 of cable 3 engages corresponding concentric contact members 33 and 34.

The insulating block 19 is also provided with annular rims 37-37 which embrace the corre sponding terminal members 22 and 24 of the high tension cables 3 and 2 respectively.

The contact member 33 is connected to one end of the secondary winding 63 of the transformer and the contact member 34 is connected to a tap of winding 63, provided close to this end of the winding, whereby a suitable voltage for the heating of the cathode filament 13 is obtained. The anode contact member 36 is connected to the other end of the secondary winding 63.

As is shown in detail in Fig. 3, a block 38, of insulating material which may be artificial resin, for instance the material known under the trade name of Bakelite, is disposed at the cathode end of the tube within the metal envelope 16, but outside of the container of the X-ray tube; the block 38 having a portion extending into the cavity formed by the re-entrant portion of the container. The block 38 is provided with a cavity 69 corresponding in shape to the end of the terminal piece 21.

Embedded in the block 38 are metal tubes 39 and 40 into'which extend respectively the lead wires 11 and 120i the incandescent cathode 13, these wires being electrically connected and secured to the tubes 39 and 40 by means of setscrews 43 and 44 respectively.

Registering with and adapted to receive the contact members 26 and 27, are provided and embedded in the insulating block 33, two concentrical cylindrical contact members 41 and 42,

into the walls of which extend the ends of the tubular members 39 and 40 respectively. Thereby the tube 39 is in electrical contact with the contact member 41, and the tube 40 is in electrical contact with the contact member 42.

When the cable 3 is to be connected to the cathode, its terminal piece 21 is inserted into the corresponding aperture of the metal envelope of the X-ray tube and the cylindrical members 26 and 27 are brought in engagement with the corresponding members 41 and 42 respectively, until the end surface 28 of the terminal piece 21 is brought to bear against a corresponding surface 68 of the insulating block 38.

The insulating block is so shaped that the inserted terminal piece 21 intimately contacts over its entire surface with the cavity 69 of the insulating block 38. As stated, the surfaces 28 and 68 of the terminal piece and of the insulating block respectively are inclined with regard to the electrical lines of force.

As shown in Figs. 3 and 4, the upper part of the cylindrical block 38 is cut away so as to provide for, an air passage, to promote air circulation.

The metallic sheath 3' of the cable 3 is shown is indicated on the drawing. From the end portion of the cable, which extends into the terminal piece 21, the metal sheath is removed and where the metal sheath ends there is secured thereto a metal washer 55.

Arranged in series with the cathode filament 13 and inserted in the lead wire 12, is a resistor 46 which falls outside of the tube container'and within the cavity of the re-entrant glass portion of the container.

The terminal pieces are provided with metal rings 47 which, as shown in Fig. 3, bear against the washer 55, whereby the contact surface between the terminal piece 21 and the ring 4'7 is not perpendicular to the conductor of the cable, but is preferably curved in such a manner that the ring surface is convex.

The cables are secured to the X-ray tube and to the transformer respectively, by means of hoods, for instance by means of gland nuts 48. As shown in Fig. 3, the gland nut 48 surrounds the ring 4'? and the washer 55, and also part of the terminal piece 21. The gland nut 48 is provided in its upper portion with internal threads and the metal envelope is provided with an externally threaded boss 49, to which the gland nut can be screwed.

To connect the tube with the transformer the two cables are connected with their respective ends to the tube and to the transformer. For instance, to connect the cathode cable to the tube, the terminal piece 21 is forced against the block 38 to establish electrical connections between members 26 and 27, and'41 and 42 respectively. Similarly connections are established between the anode cable 2 and the tube, and also between the other ends of the cathode and anode cables and the transformer. The glandnuts 48are screwed tight to the corresponding threaded bosses of the metal envelopes of the X-ray tube and of the transformer respectively and also establish electrical connections between the metal sheaths of the'cables and the metal envelopes of the tube and of the transformer.

As will be noted, the entire equipment, including the terminal pieces, is surrounded by metal envelopes so that the grounding at 50 of the metal housing 20 of the transformer also grounds the metal envelope of the X-ray tube and the outer sheaths of the cables 2 and 3.

To make the cables 2 and 3 flexible, a flexible outer sheath is used which may also consist of flexible rings engaging each other, in known manner, and capable of relative displacement with respect to each other; at the same time constituting a continuous metallic envelope of the cable.

Fig. 5 shows a slightly different shape of the anti-cathode, of the X-ray tube, whereby the cooling rod of the anti-cathode is directly surrounded at its end by an insulating block 52, which partly extends into the, cavity formed by the re-entrant portion ofthe glass portion 5 of the container.

The X-ray installation according to the invention can be easily dismounted by unscrewing the gland nuts 48 and removing the cables from the respective apertures of the metal envelopes of the X-ray tube and of the transformer.

Fig. 1 shows an X-ray installation embodying the invention as assembled for operation. The X-ray tube 1, is mounted on an adjustable arm shiftably carried by a standard, and is connected to consist of a basket weave of metal wires, as.

to the transformer 4 by means of the flexible cables 2 and 3.

To facilitate conveyance of the transformer, a handle 51 may be provided as shown in Fig. 6, which may be secured in the apertures of the cables, said handle being secured in said apertures by means of gland nuts 5353; the handle thereby closing the apertures.

No attempt is made to claim in the present application the exact form of the connecting means cooperating with and forming part of the transformer housing, such features being taught-in my copending application above referred to, now Patent No. 1,891,139.

It is of course, obvious that my invention is susceptible to numerous modifications and adaptations, and accordingly it is intended to be limited only by the scope of the appended claims.

What I claim is: 1

1. In an X-ray installation, an X-ray tube, high tension supply cables including current leads for said tube, means for electrically and mechanically connecting the cables to the tube, said means comprising contact members and members of insulating material which tightly engage the cable ends, and a conductive envelope enclosing said tube and said contact members, said envelope being provided with apertures through which extend the ends of the cables.

2. In an X-ray installation, an X-ray tube, and

high tension supply cables, having current leads for said tube, electrodes in said tube, means for electrically and mechanically connecting the cables to the tube, a conductive envelope enclosing said X-ray tube and at least part of said H means, said envelope being provided with apertures through which extend the cables into the envelope, said means including contact members for electrically connecting said cables to said electrodes, and means to increase the leakage paths between said contact members and said conductive envelope.

3. In an X-ray installation, an X-ray tube, high tension supply cables including current leads for said tube, means for mechanically and electrically connecting said cables to the tube, a conductive envelope enclosing said X-ray tube and at least part of said means, said envelope being provided with apertures through which extend the cables into said envelope, said means including contact members for electrically connecting said cables to said electrodes, and means provided between said contact members and said conductive envelope to increase the resistance of the leakage path and the breakdown distance between same.

4. In an X-ray installation, an X-ray tube, high tension supply cables including current conductors for the said tube, means, including contact members, for electrically connecting the cables to the tube, a terminal piece of insulating material, fixed on the end of each of the said cables and traversed by the current conductors of the cables and tightly engaging the said means, a conductive envelope enclosing the said means together with the X-ray tube, the said envelope being provided with apertures through which ex-' tend the terminal pieces of the cables.

5. In an X-ray installation, an X-ray tube, high tension supply cables including current conductors, means, including contact members, for electrically connecting the cables to the tube, a conductive envelope enclosing the said means together with said X-ray tube, and a terminal piece of insulating material fixed on the end of each of the said cables and traversed by the current con ductors, the said terminal pieces extending through apertures in the said envelope and tightly engaging the said means, and having a corrugated profile.

6. An X-ray installation, comprising an X-ray tube, anda high tension supply transformer, high tension insulated cables including current conductors between the tube and the transformer, conductive envelopes enclosing the said tube and the said transformer respectively, means including contact members, for electrically connecting the cables with the tube, and terminal pieces of insulating material fixed one on each end of said cables and traversed by the current conductors of the cables and tightly engaging the said means, the said terminal pieces extending through apertures in the conductive envelopes of the tube and the transformer respectively.

'7. In an X-ray installation, an X-ray tube, high tension supply cables including current conductors, means including contact members for electrically connecting the cables with the tube, a conductive envelope surrounding the said cables and the said means together with the said tube, and a terminal piece of insulating material fixed on the end of each of the said cables and traversed by the current conductors, said terminal piece having a concave front surface bearing on a complemental surface of the said means.

8. In an X-ray installation, an X-ray tube having an anode and a cathode, lead wires for the cathode, a block of insulating material, a high tension supply cable having two conductors, the said block having a recess therein, a conductive envelope enclosing the tube and the lead wires, the said envelope having an aperture therein, the said lead wires being enclosed within the said block of insulating material and terminating in bi-polar members, which are arranged at the bottom of the said recess in the said block in the rear of the aperture in said env'elope, a terminal piece of insulating material fixed on the end of the said cable, which tightly engages said recess, the said terminal piece extending through the said aperture andbeing traversed by the conductors of the cable, and contact members carried by the said terminal piece and connected to the said conductors, adapted to engage said bi-polar contact members.

9. In an X-ray installation, an 'X-ray tube having a cathode andan anode, an external current conducting rod secured to the anode, a high tension supply cable including a conductor, a block of insulating material surrounding at least a portion of the said rod, a conductive envelope surrounding the tube, the rod, and the block, the said envelope having an aperture therein, contact means on the said rod for electrically connecting it with the said cable, a conductive sleeve on said cable, said block being formed with a re cess, a terminal piece of insulating material fixed on the end of the cable and extending through an aperture in said envelope, the said recess adapting itself tightly to the contour of the said terminal piece, the said terminal piece being traversed by said cable conductor, and a contact member connected to the said conductor, and carried by said terminal piece, said contact member being adapted to engage the contact means of said rod.

10. In an X-ray installation, an X-ray tube having a cathode and an anode, an external cooling rod secured to the anode, a high tension supply cable comprising a current conductor, a conducting envelope enclosing the said tube, the said ductor, the cooling rod having an end portion.

shaped to correspond to said concave surface and tightly engaging same.

11. An X-ray installation, comprising an X-ray tube, a high ension supply transformer, conductive envelop l enclosing the tube and the trans former respectively,-the envelope for the transformer having apertures therein, high tension cables having conductors therein and connecting the tube with the transformer, terminal pieces of insulating material fixed to the ends of the said cables and being traversed by the conductors of the cables, contact members on the terminal pieces for electrically connecting the cables with the tube and the transformer respectively, a blocl; of insulating material mounted within the transformer envelope, and contact members carried by the said block and serving as terminals for the highv tension winding of the transformer, the terminal pieces of the cables which extend through the apertures of the transformer envelope bearing tightly against the said block, the contact members of the terminal pieces engaging the contact members of the transformer.

12. An X-ray installation comprising an X-ray tube, having electrodes, a high tension supply transformer, conductive envelopes enclosing the tube and transformer respectively, and cables having electrical conductors therein connecting the tube and the transformer, said cables being provided with metallic sleeves insulated for high tension from the current conductors, said tube having a conductive middle portion which is insulated from the electrodes of the tube and is electrically connected to the tube envelope, said tube envelope being electrically connected by means of the metallic sleeves with the transformer envelope, the transformer envelope being in electrical connection with the midpoint of the high tension winding of the transformer.

13. An X-ray installation, comprising an X-ray tube, a high tension supply transformer, conductive envelopes having apertures therein and enclosing the tube and transformer respectively, high tension insulated cables connecting the tube and the transformer, terminal pieces of insulating material fixed on the ends of the cables and projecting through the apertures in the conductive envelopes, and means for securing said cables to said conductive envelopes comprising threaded nipples surrounding said apertures, a gland nut screwed on said nipple, and a metal washer therein surrounding the cables, the said Washer tightly engaging the back side of said terminal pieces and being curved in the direction of the cable.

14. In an X-ray installation, an X-ray tube having a cathode, an anode, and an external current conducting rod secured to the anode, two high tension supply cables comprising current conductors, one leading to the cathode, and the other leading to the anode, a block of insulating material surrounding at least a portion of the said rod, a conductive envelope surrounding the tube, the rod, and the block, the said envelope having an aperture therein, contact means on the said rod for electrically connecting it with the anode cable, said block being formed with a recess, a terminal piece of insulating material fixed on the end of the anode cable and extending through an aperture in said envelope, the said recess adapting itself tightly to the contour of the said terminal piece, the said terminal piece being traversed by the conductor of the anode cable and a contact member carried by same and connected to the said conductor, and adapted to engage the contact means of said current conducting rod.

15. In an X-ray installation, an X-ray tube, having a cathode, an anode, and an external cooling rod secured to the anode, two high tension supply cables comprising current conductors, one leading to the cathode and the other leading to the anode, a conducting envelope enclosing the said tube, the said envelope having an aperture therein, a terminal piece of insulating material fixed to the end of the anode cable and being traversed by the current conductor of the anode cable, said terminal piece extending through the aperture in the said envelope, and having a concave front surface, and a contact member secured in the said concave front surface, and connected to the said current conductor, said cooling rod having an end portion shaped to tightly engage said concave surface.

16. In an X-ray installation, an X-ray tube having an anode and a cathode, lead wires for the cathode, a high tension supply cable having two conductors, and leading to the cathode, a block of insulating material having a recess therein, a conductive envelope enclosing the tube, and the lead wires, the said envelope having an aperture therein, the said lead wires being enclosed within the said block of insulating material and terminating in bi-polar contact members, arranged at the bottom of the recess in the said block in the rear of the aperture in said envelope, a terminal piece of insulating material fixed on the end of the cathode cable, and which tightly fits said recess, the said terminal piece extending through the said aperture and being traversed by the conductors of the cathode cable, and contact members carried by the said terminal, connected to the said conductors, and adapted to engage the bi-polar contact members of the cathode lead wires, and a single conductor high voltage cable leading to the anode.

ALBERT BOUWERS. 

